Dreaming of Streaming: The Math Behind The Strategy

Imploring fantasy footballers to wait until the waning rounds to invest in a defense doesn’t require the arm twisting needed to convince people to skimp on quarterback.

It’s hardly groundbreaking to advocate a streaming approach to the inherently volatile team defense (D/ST) position, though every year as the NFL season approaches, voices emerge from the fantasy football wilderness pledging, unequivocally, to invest in a (reportedly) top-flight defense in the middle rounds.

After all, we want the best of everything, right? We want the best clothes and cars and mobile gadget thingies and quarterbacks and running backs and receivers and, yes, defenses — the best defenses the NFL has to offer. What’s better than the best? Nothing.

This logic meshes seamlessly with disciples of the misguided lineup-filling approach to fantasy football drafts. Lineup filling, for those unfamiliar with the term, is when a fantasy gamer seeks only to compose a starting lineup with her first seven or eight picks, paying no mind to bench spots.

I have my three receivers, my two starting runners, my tight end and quarterback? Well, it’s time to choose a defense. (You’ve just been plugged into the ever-churning brain of an avowed lineup filler. Now run, take a shower and try to purge this from your degenerate mind.

I understand the temptation of lineup filling, but I promise that your roster will be more reliable, robust, and generally less prone to injuries if you pass on defenses until the very late rounds.

These defensive units rely on predictably unpredictable events like defensive touchdowns, interceptions, fumble recoveries, and to a less extent, sacks.

Rushing yards, passing yards, and receiving yards are practically easy to project in comparison. There’s also no scarcity of weekly defensive options, unless you’re in a 16-team league with huge rosters. I’d still stream in that format.

D/ST production gaps

Another reason we invest highly in running backs and wide receivers is because that fantasy production is not replaceable. If you treat those points as replaceable, you’ll regret it over the long haul, even if things break right for you here and there.

Part of the way we measure replaceability is to find the difference between a position’s top performers and those at the edge of fantasy usefulness. The larger the gap, the harder it will prove to replace the production of players who dominate their positions.

Below is a breakdown of positional replaceability over the past three seasons.

Difference between QB1 and QB12

Difference between RB1 and RB24

Difference between WR1 and WR24

Difference between TE1 and TE12

Difference between D/ST1 and D/ST12

2011

38.8%

52.1%

45.9%

50.6%

30.1%

2012

24.8%

55.2%

48.1%

37.2%

37.8%

2013

38.4%

53.9%

36.8%

43.8%

43.5%

There’s a caveat to the production gaps between No. 1 defenses and No. 12 defenses, however. No one in their right mind should play the season’s 12th best defense every week, no matter what.

Last year’s No. 12 defense, the Baltimore Ravens, had six games in which they failed to score five fantasy points. The Ravens’ defense notched zero or negative points four times. If you started Baltimore for 16 consecutive weeks, you either bleed purple and black — which you should get check out, posthaste — or you are in need of a straightjacket.

There’s another piece to this defensive production gap puzzle, of course: the top defenses are often not the units so highly sought after in the middle parts of fantasy drafts. There are rare exceptions, of course, but it wouldn’t be wise to talk to 2013 Kansas City Chiefs D/ST owners about those exceptions.

They got their elite defense in the 16th round.

Reaching instead of streaming

I think too much of our D/ST conversation is reliant on anecdotal evidence, whether or not you support the sensible streaming approach. I wanted to see where Top Five defensive units have been drafted since 2011. The results, I must confess, were less than shocking.

ADP of D/ST1

ADP of D/ST2

ADP of D/ST3

ADP of D/ST4

ADP of D/ST5

2011

14.06

10.02

9.04

11.09

8.02

2012

10.04

14.01

12.08

13.04

14.11

2013

16.07

7.04

15.12

10.06

13.07

In two of the past three NFL seasons, fantasy’s top defense was nabbed in the 14th round or later. The 2012 Chicago Bears, a unit that finished well above the second-best defense, was the exception here. It’s worth noting that Chicago was the seventh defense off the draft board in 2012, according to MyFantasyLeague ADP data.

A couple highly-touted defenses cracked the Top Five in 2013 (Seattle) and 2011 (Jets), but the point is clear: Beyond the obvious and proven viability of streaming defenses, every-week no-brainer starters emerge from the depths of our fantasy drafts, unlike any other position not called kicker.

The central takeaway from the above chart: Defensive scoring is more random than any of us would like to admit, even those of us who fancy ourselves game-watching gurus. We’re not all that concerned with spotting an every-week starting D/ST — since there are so many startable options on the wire every week — but it’s good to see so many late round defenses finding their way into elite territory.

I thought a quick look at how these middle-round defensive selections fared would be an instructive exercise, so I pieced together the data below.

2011

2012

2013

AVERAGE

ADP of 1st D/ST off the board

6.09 (finished as D/ST13)

7.01 (finished as D/ST8)

7.04 (finished as D/ST2)

7.01 ADP

This might seem like information that supports the drive to select a D/ST in the sixth or seventh round, but that thinking completely ignores opportunity cost. In other words, focusing solely on the Seahawks finishing as fantasy’s No. 2 defense in 2013 fails to recognize what you had to give up to secure Seattle’s defensive services.

You would’ve given up your chance to nab Jordan Cameron, whose breakout campaign landed him inside the Top Five fantasy tight ends. You would’ve passed up on Josh Gordon before he went nuclear and finished as fantasy’s most valuable player. Drafting Seattle would have likely forfeited your chance to draft Anquan Boldin — a Top 14 receiver — and Le’Veon Bell, who scored more points than all but eight running backs from Week 3-17.

It’s that opportunity cost that gets lost in the summertime defensive chatter.

Next week I’ll highlight some of the best Week 1 streamers, along with two late-round units that could easily turn into unquestioned every-week defenses in 2014.

Great article, its nice to see numbers that back up this strategy. I generally stream unless I hit Gold with a defense long the Way. My question is who is the defense your likely targeting in week 1 that can be had at the end of the draft.